Jacinta Allan will face a vote of no confidence as the Victorian premier's would-be replacement seeks to hold her feet to the fire.
Opposition Leader Jess Wilson will give notice to state parliament's lower house on Thursday that the coalition plans to move a motion of no confidence in the premier and her ministers.
Only one motion of no confidence can be moved each four-year term and can lead to the dissolution of parliament if passed, well before the scheduled state election on November 28.